Circulating-Water Mattress Enhances Thermal Comfort and Patient Satisfaction but Shows Non-Superiority in Temperature Maintenance in Ophthalmic Day-Case Surgery: A Randomized Controlled Trial.

Purpose: Perioperative hypothermia, a common complication of general anesthesia, is associated with adverse outcomes. While active warming methods are recommended, the effectiveness of circulating-water mattresses during ophthalmic surgeries remains understudied. This randomized controlled trial assessed whether a circulating-water mattress combined with a cotton quilt (Group W) was superior to a cotton quilt alone (Group C) in maintaining patient body temperature during ophthalmic day-case surgery.

Patients and methods: Group W patients (n=39) used a preheated circulating-water mattress (38°C) on the operating table and were covered with a cotton quilt (from their entry to the operating room until they returned to the ward). Group C patients (n=38) lay on an unheated table and were covered with a cotton quilt. The axillary temperature in the surgical waiting area served as the baseline. Axillary temperature, ambient temperature, heart rate, and mean arterial pressure were documented at anesthesia induction (T₀), start of surgery (T₁), every 5 min for the first hour (T₂-T₁₃), and end of surgery (T₁₄). Satisfaction and thermal comfort scores were assessed at baseline in the waiting area, 5 min before anesthesia induction (t₀), 15 min after entering the post-anesthesia care unit (PACU) (t₁), and upon leaving the PACU (t₂). The primary outcome measure was the axillary temperature at T₁₄.

Results: At T₁₄, Group W had a higher axillary temperature than Group C (36.40±0.06°C vs 36.18±0.06°C, P=0.011), with the mean difference 0.22°C, which did not exceed the predefined superiority threshold of 0.30°C, indicating that the warming effect in Group W was not superior to that in Group C. However, thermal comfort and satisfaction scores were significantly enhanced at t₀ and t₁ (P<0.05).

Conclusion: During ophthalmic day-case surgeries, a circulating-water mattress plus a cotton quilt was not superior, regarding their warming effect, but they significantly enhanced patients' thermal comfort and satisfaction.